In the known drilling device over which the present invention is an improvement, in order to transmit the torque from the oscillating drive to the drill rod assembly, the drill rods are provided with a contour so that an interlocking results (see German Patent Document 38 42 081 and U.S. Pat. No. 5,092,411). The same result may be realized by means of a clamping device. The advance as well as the extraction are performed via the chain drive of the flushing head. As soon as the slide reaches its lower position and the flushing head has been retracted into its upper starting position, a new drill rod from a drill rod magazine can be inserted. The spent drill rod assembly in the bore hole is kept in place in the usual manner by a mounting head. At this point, the slide is brought back to its upper position via a special drive.
While the slide is being brought back to this position, the hydraulic hoses are pressed into the longitudinal channels of the newly inserted drill rod by the hose insertion and retraction mechanism, whereafter the boring operation of the newly inserted drill rod can start. When the rod system is pulled out, the process takes place in reverse order, whereby from each of the removed drill rods the hydraulic hoses are pushed out by the retraction elements during the travel of the slide. When the drill rods are designed as hollow rods, the flushing air is supplied through them. However, if they are made of a solid material, the flushing air for the intra-hole hammer cannot be blown through the interiors of the drill rods, so that they must be equipped with ducts for the blast air.